End brushes or finishing tools are often manufactured utilizing rings, sleeves, pins or keys as anchors to secure the filament bundle in the cap of the shank with the filament bundle being folded as a hairpin in the cup of the shank. This results in a non-uniform distribution and density of the filaments and also normally requires secondary operations such as trimming of the brush face and crimping or swaging of the lip of the cup. Such internal anchors can in and of themselves affect the dynamic balance of the tool quite apart from causing non-uniform distribution of the filaments. Examples of end brushes or tools using mechanical anchors or keys may be seen in prior U.S. Pat. Nos. 2,982,983, 3,312,993, and 2,421,647.
As indicated in the latter two patents a solder or adhesive may be used in addition to the key or other anchor with the preferred adhesive in U.S. Pat. No. 2,982,983 being epoxy resins. Many adhesive systems are too viscous, difficult to apply and use and require a substantial cure time. If the preferred filament is a plastic, such as a polyamide with abrasive heavily loaded therein it is difficult to bond the filaments uniformly with an adhesive to a metal or plastic shank without the aid of an anchor and the attendant problems. The adhesive should be a low viscosity liquid which can be readily metered and which when applied to the bottom of the cup of the shank will uniformly cover the bottom of the cup to a uniform depth. Moreover, the adhesive should not be a two-part system such as epoxy and should cure quickly.
A method of manufacture of such tool should enable the tool to be made and assembled quickly without secondary operations such as the trimming of the tool face or modification of the shank to enhance the securing the filament bundle to the shank.